[openwrt/openwrt] scripts: download-check-artifact.sh: fix shellcheck and improve

[LEDE Commits]

ynezz pushed a commit to openwrt/openwrt.git, branch openwrt-24.10:
https://git.openwrt.org/8f0d52d8c42234ffd6292e6e2d6490987c92e624

commit 8f0d52d8c42234ffd6292e6e2d6490987c92e624
Author: Petr Štetiar <ynezz at true.cz>
AuthorDate: Wed Nov 6 10:40:37 2024 +0000

    scripts: download-check-artifact.sh: fix shellcheck and improve
    
    Fixes following shellcheck's recommendations:
    
     In scripts/download-check-artifact.sh line 24:
            exit $1
                 ^-- SC2086 (info): Double quote to prevent globbing and word splitting.
    
     In scripts/download-check-artifact.sh line 53:
                    local sum="$(shasum -a 256 "$image_file")";
                          ^-^ SC2155 (warning): Declare and assign separately to avoid masking return values.
    
     In scripts/download-check-artifact.sh line 72:
     cd "/tmp/verify.$$"
     ^-----------------^ SC2164 (warning): Use 'cd ... || exit' or 'cd ... || return' in case cd fails.
    
     In scripts/download-check-artifact.sh line 114:
                    printf "Keyserver to use? [$keyserver_url] > "
                           ^-- SC2059 (info): Don't use variables in the printf format string. Use printf '..%s..' "$foo".
    
     In scripts/download-check-artifact.sh line 115:
                    read url; case "${url:-$keyserver_url}" in
                    ^--^ SC2162 (info): read without -r will mangle backslashes.
    
    While at it make it clear, that it is possible to download/check any
    build artifacts like even SDK or ImageBuilder.
    
    Link: https://github.com/openwrt/openwrt/pull/16871
    (cherry picked from commit 27c2c140b16cb490f20c1c2259b3decf50ae5762)
    Link: https://github.com/openwrt/openwrt/pull/17097
    Signed-off-by: Petr Štetiar <ynezz at true.cz>
---
 scripts/download-check-artifact.sh | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/scripts/download-check-artifact.sh b/scripts/download-check-artifact.sh
index 31868da5cd..bc0918b214 100755
--- a/scripts/download-check-artifact.sh
+++ b/scripts/download-check-artifact.sh
@@ -12,6 +12,7 @@
 #  255 - A suitable download or checksum utility is missing
 
 [ -n "$1" ] || {
+	echo "$0 - Download and verify build artifacts"
 	echo "Usage: $0 <url>" >&2
 	exit 1
 }
@@ -21,7 +22,7 @@ finish() {
 		echo "Cleaning up."
 		rm -r "/tmp/verify.$$"
 	}
-	exit $1
+	exit "$1"
 }
 
 trap "finish 254" INT TERM
@@ -50,7 +51,8 @@ if which sha256sum >/dev/null; then
 	checksum() { sha256sum -c --ignore-missing "sha256sums"; }
 elif which shasum >/dev/null; then
 	checksum() {
-		local sum="$(shasum -a 256 "$image_file")";
+		local sum
+		sum="$(shasum -a 256 "$image_file")";
 		grep -xF "${sum%% *} *$image_file" "sha256sums";
 	}
 else
@@ -68,11 +70,14 @@ else
 	}
 fi
 
-mkdir -p "/tmp/verify.$$"
-cd "/tmp/verify.$$"
+tmpdir="$(mktemp -d)"
+cd "$tmpdir" || {
+	echo "Failed to create temporary directory!" >&2
+	finish 255
+}
 
 echo ""
-echo "1) Downloading image file"
+echo "1) Downloading artifact file"
 echo "========================="
 download "$image_file" "$image_url" || {
 	echo "Failed to download image file!" >&2
@@ -111,8 +116,8 @@ if [ -n "$missing_key" ]; then
 	echo ""                                                                  >&2
 
 	while true; do
-		printf "Keyserver to use? [$keyserver_url] > "
-		read url; case "${url:-$keyserver_url}" in
+		printf 'Keyserver to use? [%s] > ' "$keyserver_url"
+		read -r url; case "${url:-$keyserver_url}" in
 			hkp://*)
 				gpg --keyserver "${url:-$keyserver_url}" --recv-keys "$missing_key" || {
 					echo "Failed to download public key." >&2
@@ -148,7 +153,7 @@ cp "$image_file" "$destdir/$image_file" || {
 echo ""
 echo "Verification done!"
 echo "=================="
-echo "Firmware image placed in '$destdir/$image_file'."
+echo "Downloaded artifact placed in '$destdir/$image_file'."
 echo ""
 
 finish 0